NATURE OF EXCRETURY PROCESSES IN MARINE POLYZOA. 1238 
On the Nature of the Excretory Processes in 
Marine Polyzoa. 
By 
Sidney F. Harmer, M.A., B.Sc., 
Fellow and Assistant Tutor of King’s College, Cambridge. 
With Plates IT and I1I. 
Tue observations described below were made during an 
occupation of the Cambridge University table at the Zoological 
Station at Naples, in the course of the Easter vacation, 1891. 
The results obtained by Kowalevsky! on the excretion of car- 
minate of ammonia and of indigo-carmine in various Inver- 
tebrates had suggested an inquiry, by means of the same 
methods, into the physiological meaning of the periodic forma- 
tion of ‘‘ brown bodies” in Ectoproctous Polyzoa, since there 
seemed reason to suppose that this process might serve as a 
means of excretion, a view which has been most definitely 
formulated by Ostroumoff.? My experiments made with arti- 
ficial pigments confirm the view that the marine Ectoprocta 
are not provided with definite nephridia ; and appear to show 
that the excretory processes are carried on principally by the 
“brown bodies,’ the funicular (connective) tissue, and the 
free mesoderm-cells contained in the meshes of the latter. 
The species which, by reason of their transparency and of 
their abundance at Naples, were principally employed for these 
1 A. Kowalevsky, “ Hin Beitrag zur Kennt. d. Excretionsorgane,” ‘ Biolog. 
Centralblatt,’ ix, 1889-90, pp. 33, 65, 127. 
2 A. A. Ostroumoff, “Cont. & Et. Zool. et Morphol. des Bryozoaires du 
Golfe de Sebastopol,” ‘ Arch. Slaves de Biol.,’ t. ii, 1886, p. 339. 
